299 research outputs found
Comparative transcriptome profiling of the injured zebrafish and mouse hearts identifies miRNA-dependent repair pathways.
The adult mammalian heart has poor regenerative capacity. In contrast, the zebrafish heart retains a robust capacity for regeneration into adulthood. These distinct responses are consequences of a differential utilization of evolutionary-conserved gene regulatory networks in the damaged heart. To systematically identify miRNA-dependent networks controlling cardiac repair following injury, we performed comparative gene and miRNA profiling of the cardiac transcriptome in adult mice and zebrafish.
Using an integrated approach, we show that 45 miRNA-dependent networks, involved in critical biological pathways, are differentially modulated in the injured zebrafish vs. mouse hearts. We study, more particularly, the miR-26a-dependent response. Therefore, miR-26a is down-regulated in the fish heart after injury, whereas its expression remains constant in the mouse heart. Targets of miR-26a involve activators of the cell cycle and Ezh2, a component of the polycomb repressive complex 2 (PRC2). Importantly, PRC2 exerts repressive functions on negative regulators of the cell cycle. In cultured neonatal cardiomyocytes, inhibition of miR-26a stimulates, therefore, cardiomyocyte proliferation. Accordingly, miR-26a knockdown prolongs the proliferative window of cardiomyocytes in the post-natal mouse heart.
This novel strategy identifies a series of miRNAs and associated pathways, in particular miR-26a, which represent attractive therapeutic targets for inducing repair in the injured heart
Globalisation, economic growth and energy consumption in the BRICS region: the importance of asymmetries.
This paper examines the asymmetric impact of globalisation and economic growth on energy consumption in BRICS countries, applying the NARDL bounds approach to explore the presence of asymmetric cointegration across variables. The empirical results reveals that energy consumption is positively and negatively affected by the positive and negative globalisation shocks, respectively. A positive shock in economic growth promotes energy consumption, while a negative shock reduces energy consumption.N/
Study of a Swiss dopa-responsive dystonia family with a deletion in GCH1: redefining DYT14 as DYT5.
OBJECTIVE: To report the study of a multigenerational Swiss family with dopa-responsive dystonia (DRD).
METHODS: Clinical investigation was made of available family members, including historical and chart reviews. Subject examinations were video recorded. Genetic analysis included a genome-wide linkage study with microsatellite markers (STR), GTP cyclohydrolase I (GCH1) gene sequencing, and dosage analysis.
RESULTS: We evaluated 32 individuals, of whom 6 were clinically diagnosed with DRD, with childhood-onset progressive foot dystonia, later generalizing, followed by parkinsonism in the two older patients. The response to levodopa was very good. Two additional patients had late onset dopa-responsive parkinsonism. Three other subjects had DRD symptoms on historical grounds. We found suggestive linkage to the previously reported DYT14 locus, which excluded GCH1. However, further study with more stringent criteria for disease status attribution showed linkage to a larger region, which included GCH1. No mutation was found in GCH1 by gene sequencing but dosage methods identified a novel heterozygous deletion of exons 3 to 6 of GCH1. The mutation was found in seven subjects. One of the patients with dystonia represented a phenocopy.
CONCLUSIONS: This study rules out the previously reported DYT14 locus as a cause of disease, as a novel multiexonic deletion was identified in GCH1. This work highlights the necessity of an accurate clinical diagnosis in linkage studies as well as the need for appropriate allele frequencies, penetrance, and phenocopy estimates. Comprehensive sequencing and dosage analysis of known genes is recommended prior to genome-wide linkage analysis
Globalisation, economic growth and energy consumption in the BRICS region: the importance of asymmetries.
This paper examines the asymmetric impact of globalisation and economic growth on energy consumption in BRICS countries, applying the NARDL bounds approach to explore the presence of asymmetric cointegration across variables. The empirical results reveals that energy consumption is positively and negatively affected by the positive and negative globalisation shocks, respectively. A positive shock in economic growth promotes energy consumption, while a negative shock reduces energy consumption.N/
Mol Vis
PURPOSE: To analyze in vivo the function of chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C (gene symbol: Cspg5) during retinal degeneration in the Rpe65(-)/(-) mouse model of Leber congenital amaurosis. METHODS: We resorted to mice with targeted deletions in the Cspg5 and retinal pigment epithelium protein of 65 kDa (Rpe65) genes (Cspg5(-)/(-)/Rpe65(-)/(-)). Cone degeneration was assessed with cone-specific peanut agglutinin staining. Transcriptional expression of rhodopsin (Rho), S-opsin (Opn1sw), M-opsin (Opn1mw), rod transducin alpha subunit (Gnat1), and cone transducin alpha subunit (Gnat2) genes was assessed with quantitative PCR from 2 weeks to 12 months. The retinal pigment epithelium (RPE) was analyzed at P14 with immunodetection of the retinol-binding protein membrane receptor Stra6. RESULTS: No differences in the progression of retinal degeneration were observed between the Rpe65(-)/(-) and Cspg5(-)/(-)/Rpe65(-)/(-) mice. No retinal phenotype was detected in the late postnatal and adult Cspg5(-)/(-) mice, when compared to the wild-type mice. CONCLUSIONS: Despite the previously reported upregulation of Cspg5 during retinal degeneration in Rpe65(-)/(-) mice, no protective effect or any involvement of Cspg5 in disease progression was identified
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Acute Hypoglycemia Induces Retinal Cell Death in Mouse
BACKGROUND: Glucose is the most important metabolic substrate of the retina and maintenance of normoglycemia is an essential challenge for diabetic patients. Glycemic excursions could lead to cardiovascular disease, nephropathy, neuropathy and retinopathy. A vast body of literature exists on hyperglycemia namely in the field of diabetic retinopathy, but very little is known about the deleterious effect of hypoglycemia. Therefore, we decided to study the role of acute hypoglycemia in mouse retina. METHODOLOGY/PRINCIPAL FINDINGS: To test effects of hypoglycemia, we performed a 5-hour hyperinsulinemic/hypoglycemic clamp; to exclude an effect of insulin, we made a hyperinsulinemic/euglycemic clamp as control. We then isolated retinas from each group at different time-points after the clamp to analyze cells apoptosis and genes regulation. In parallel, we used 661W photoreceptor cells to confirm in vivo results. We showed herein that hypoglycemia induced retinal cell death in mouse via caspase 3 activation. We then tested the mRNA expression of glutathione transferase omega 1 (Gsto1) and glutathione peroxidase 3 (Gpx3), two genes involved in glutathione (GSH) homeostasis. The expression of both genes was up-regulated by low glucose, leading to a decrease of reduced glutathione (GSH). In vitro experiments confirmed the low-glucose induction of 661W cell death via superoxide production and activation of caspase 3, which was concomitant with a decrease of GSH content. Moreover, decrease of GSH content by inhibition with buthionine sulphoximine (BSO) at high glucose induced apoptosis, while complementation with extracellular glutathione ethyl ester (GSHee) at low glucose restored GSH level and reduced apoptosis. CONCLUSIONS/SIGNIFICANCE: We showed, for the first time, that acute insulin-induced hypoglycemia leads to caspase 3-dependant retinal cell death with a predominant role of GSH content
Exchange rate volatility and UK imports from developing countries: The effect of the global financial crisis
This paper studies the role of exchange rate volatility in determining the UK's real imports from three major developing countries – Brazil, China, and South Africa. The paper contributes to the literature by investigating the third country effect and also by analyzing the impact of the current financial crisis on the relationship between exchange rate volatility and UK imports. This paper further expands the empirical literature on the subject by offering evidence based on the asymmetric autoregressive distributed lag (ARDL) method from the application of monthly data from January 1991 to December 2011. Results suggest that exchange rate volatility plays an important role in determination of trade and also reveal a significant effect of the recent financial crisis on UK imports. This finding remains consistent when we test for the third country volatility effect. We also find that there is a significant causal relationship between exchange rate volatility and UK imports. The third country effect is significant for all the countries investigated. These results have significant implications for the trade policy and international trade in minimizing the underlying risk factors and ensuring stable trade flows in different economic scenarios
In vitro antibacterial activity and acute toxicity studies of aqueous-methanol extract of Sida rhombifolia Linn. (Malvaceae)
<p>Abstract</p> <p>Background</p> <p>Many bacteria among the Enterobacteria family are involved in infectious diseases and diarrhoea. Most of these bacteria become resistant to the most commonly used synthetic drugs in Cameroon. Natural substances seem to be an alternative to this problem. Thus the aim of this research was to investigate the <it>in vitro </it>antibacterial activity of the methanol and aqueous-methanol extracts of <it>Sida rhombifolia </it>Linn (Malvaceae) against seven pathogenic bacteria involved in diarrhoea. Acute toxicity of the most active extract was determined and major bioactive components were screened.</p> <p>Methods</p> <p>The agar disc diffusion and the agar dilution method were used for the determination of inhibition diameters and the Minimum Inhibitory Concentration (MICs) respectively. The acute toxicity study was performed according WHO protocol.</p> <p>Results</p> <p>The aqueous-methanol extract (1v:4v) was the most active with diameters of inhibition zones ranging from 8.7 - 23.6 mm, however at 200 μg/dic this activity was relatively weak compared to gentamycin. The MICs of the aqueous-methanol extract (1v:4v) varied from 49.40 to 78.30 μg/ml. <it>Salmonella dysenteriae </it>was the most sensitive (49.40 μg/ml). For the acute toxicity study, no deaths of rats were recorded. However, significant increase of some biochemical parameters such as aspartate amino-transferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and creatinine (CRT) were found. The phytochemical analysis of the aqueous methanol extract indicated the presence of tannins, polyphenols, alkaloids, glycosides, flavonoids and saponins</p> <p>Conclusion</p> <p>The results showed that the aqueous-methanol extract of <it>S. rhombifolia </it>exhibited moderate antibacterial activity. Some toxic effects were found when rats received more than 8 g/kg bw of extract.</p> <p><it>Antibacterial; Enterobacteria; Acute toxicity; Phytochemical analysis</it></p
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